Piston-ring.



J. A'CHARTER.' I

PISON RING. y

APPLncATloN FILED 0m11.191s.

1,250,431. f Patented Deo; 18,1917.

2 SHEETS-SHEETL l.

1.'. A.CHARTER.

PISTON RING.

APPLICATION msn 11m11.191s.

1,250,43 1 Patented, D ec. 18, 1912 2 sHEETs-SHEET 2.

struct vthe-ri' each offwhi f part operating fof wed'gevthe other. part or x l Experiencehastaught that,when;

,umts A. cnnn'rnn, o'F emailen, rumors.'

PISTON-BIG.

negentien @letters Patent.

' Patented Dec. 18,1017.

Anmut .nen wenn n, 191- Se'rw Re 186,185.

I circumferntialsurface on the ring but a1so for the wearfon the sides ofthe rinlg und the 4115 roximete or contacting sides of 'for the Wearon the circumferentialsu'rface ofc-the ringbys liningt -vari'egls.minimis` have been ,emp oyedgfor .pompen'sating-jfor side wear-.f1 '.OneV is' to conf in twaor more muti ports isl splitf ende, one

Il n rlrsfasfwear occll'm. and thuskeep 'a ti ht t both-utgthe lpem'phfc yoftheruig an at ereof 4w f ,contact is made f Rmgsof-thischarcter in'ay be termed comy pound'rigs "in A 'split ringswhich Aare also commonly knoln ,nu in the art. But 'one' of the disfulvan'tggee 0f `the compound rin 4heretofmife known is 'thet they produce iierent amountsfof wear at diierentzf-point's of the circumference..

is' concentric in internal andjcxt .eter the radiel'pressure, and hence the wear on the cylinder., is Vgreater nearthe ends,l where the rings are split, than at the points lfarther reinotefrom said ends., One of Vthe iobjects of my invention is -to producen cnioundin which will combine the Vcharacsure at all points o e circumference and at thesame'txme keep the parte4 gas'ti htv not only atthe suracewhere the rin ru s upon the c lind'er but 4also at 'the sur Yllcesfwhere the ring contacts the two sides o f the groove in the piston."

f'lition illustrated `in .the accompanying drawv igure 1` is e' face view of the 4,muster ring in alembled position;

Fig. 2 is a corresponding face view of Ythe .'wsecondary-rng. V

e grooveI m the'piston. It' iscommon to compensate position after wnsidcmbl Weill' 911 the masproducingl'e.' uniformjadialpres- Fi L3 is a section of the master ring on tlie` Ima-einig f Fig. 4 1s section of the secondary. ring. on the liI 1 e 4I-4, Fig. 2. -1 4 80 Fig. 5 1s a fragmentary detail showing the two rin and associated portions of the piston an cylinder i'n assembled positio'ufthe thickest section of the master ring showing. Figs, 6 n il Z show respectively the muster and secon 4:try rings w thoypistolfl--ln Fig. 8 is u cent-ral section through the pist0n Mld rings showing the rings 1n position when first assembled beforeany wear has' taken place. y Fig. 9 showsthe seme parts in working -ter ring .has'taken luce and the secondary ring has el; a'nde (with Asome weer) to .compensateV olf-this. 1- j j Snmlurl inunernls refer to simill' parte j throughout the several views. The masterringqis .identified in general ,by' referencenulneral lqand the seconder ring xngenerull by thereference numeral Y The master ring is split at the points A .in thel usual'. :and is thus. explnsible, being giada of metal more or lessresiliont. Tins-ring whenfviewed from the side, as. in Flgs` .`1gfand 7,! sjeccentricall bored, being thninest' at the 'ends and .t ckest` atthe points midway between the ends.' At. the" side whichl'eaneretto the Sendl'y Ping,` Vwhen Ythe perte am assembled, 'the master? 4o hining, as to leave' s concenblfic .outer por- -t1 on3. In consequenw etporton of the 'ring farthest, from the sp 't ndll'l' L'Shpdl 1n cross-section; as olea'rl shows, in'Figi 96j the width of theledge 4t "nning iu pro on.. tion. as it reaches thesplit ends.I` Onno the results of this 'configuretionis 'thtytg` as lsf well understood'byen thefi'ing his the advanta e that; Y e 'radially outward pressure of t e master rin upon'tbe engine cylinder 5 1s yupproxiniutc yuniform at all omts ofthe outer circum-fexem'e of the ring ue to its tapering section o r eccentrlcityql The secondary ring constitutes the means for compensatin for thel naturally occuring sicle'\`v e.'ax'.jV iis secondary rin has the same cross section at all points an its side surface 6 contacts the side surface 7' of theV groove of the piston in the usual manner. 'The surface! of thering 2, which is parallel to Vsurface 6, forman meeting N09- oo- '1 ring is so conflgurated,v preferably' by-nnt-jiy to coperate with the meeting face 9 of-the master ring 1. The surface 8, however, is but little, if any, Wider than the concentric portion 3 of the, master ring, andfroln this point is configurati-ed to a curve 10, which rises from the inner diameter of the meeting face 8. The curved surface 10 of the sec-4 ondary ring conforms approximately to the surface of a sphere` a portion of Whose sur I v`an.approxi'mately uniform outward 25 face is indicated by the broken line 11 of Fig; 4. The icsult of this construction is that the secondary ring forms a portion, as it were, of the hall of a. ball and socket joint, the analogue of the socket being represented by the annular slnmlder or corner 12 of the master ring. This quasi ball and socket joint has the effort of rompensating for the uneven wear of the master ring sidewiserthat is, in an axial direction-in the groove,

as is-shown'in Fig. 9.

Operation: The masi-cr ring` which in the preferred construction contains considerably more metal than the. second-ary ring, exerts pressure -atall points of its circumference due to-the .fact that it is constructeifl vwith the cross- Scctionalarea greatest at the'point farthest from the split ends, the section la'perin'gofl' Being resilient, it is, in'a sense,

1n proportion as it approaches the ends. a spring, ad .operates according to the vlawo.. sin-ings. which, when roperly designed a re t nckest at their middle-points. Consequently, the sameA amount-.of wear is obtained-'at all points of the circumference and the cylinder is not subject to greater wear at one point of its circumference than at nnotl'ier; This is an u nportant andy al1-obvious advantage. But

as tA e-'rnnster ring. has less side surface to .lio

-whi

hence t present to lthe side of the 'piston groove at its splitends than'it has at thefpointimidway' between, it will. sutfermorefrom Asidewise Wear atthe ends thanat, the point-"midway between. In other [pounding in an axial directi'oxtdue :to the 'constant reversal off'fmotion off-the piston will gweanthose side surfacesof the master ringfaster near tl'iesp'lit endsy of the master ring thanat the .'intern'lcl-lriate point. rl`his causes luneven wear -upon'.the sides of theA .master -ri-ng. 'This-uneven vweartends to fshiftthe plane of the ring-is a. 'whole 1 ela`f tiyelyv-to the'xs ofv the cylinder, as clearly appear-rain Fig. 9. .The ring b econ'iing''thinner, axially', and ycause a ofrv movement of t nearits split ends would lbecome Rounding at each reversal the; -AEeculiar shape of thel secondary* ring y 'al e., at A '("Figf'- 1);, there is less' wearing surface, axially, between the meetin 'surfaces 8 and 9of the two rings, ere is, as wear takes place, greater Words; *.tlie constant i' e piston were/it 4not-for compensates forthe uneven wear in .the-.manner clearly shown 1n Fig.` 9, und as Point where the master ring and hence wears more rapidly than the mus (erging, which possesses infuch more metal at its peripheral surface, due to its width of face, hut the expansion of the secondary ring at the point where vthe master ring is thinnest brings the rapidly rising curve 10 of thesecondary ring into 'engagement with the annular shoulder l2 of the masterfring and keeps the side surface 13 of the master ring always snug against the adjacentside sur face l of the'g'roovein` iston.v 1n other words, the secondary ring s toward the cylinder and awayfroni the master ring at its thinnest portioniiand by moving axially compensates for the excessive side'w'ear of the'inetalof the master ring on -this'side of the cylinder; The net result is that with my"de\'ice, the wear `u'ponthe in- 1iftsatfthis point' ner surface; of the' cylinder reminsiconstant at all points of the cireum ference and'yet' the unerei'i'wear which results, axially, in the master ring, due to its tapering' or eccentric construction, is compensated for b the 'secondary ring with its approximate y' spheri- "cal surface. This device, therefore combines two highly desirable characteristics; to-wit: the ability to maintain the wear on the cylinder uniform at all points so' tlat the cylinder will not b'ecrne yolll't-of-iound, and the'l ability to remain gas itightin all different positions of the two rings by reason of the presence of the quasisp'herical surfaceiif the secondary ring; actual'` tests showingr that other forms of suracecontact do notnroduce this'result. f

Having'- thusv describedmy invention, 1'what I claim as 'new and-desire to Secre .,by Letters Patent-fis: r1.; A compound piston: ring` havin n AI`1'1urality 'of cooperating parts, one 'of 1r ich is a split muster rin a'nd' another a'fsplit secondary' rin the masterring having an annularshoul er i1 1d' a raryin' section, lihin-ner'n'cf'rits'splitfen s', and' the secondary rin r`jhring an"approximatelv s heric'al surges: coperatingffii'thsai s oulder whereby uneven Wenaxially, of the masterfrin due 'to afsm'allercross sec- 'ti'on atone'plnt than another,fs" com ensated for'bythe c xpansionff the secon ary ,ring 'forcingthe'f np rgxiinately 'herical surface oli'v the tsecondiary ring against the master'ring. 2` A. compound piston"'rn`cmposedof two cooperating parts, a Split master ring anda split secondary ring, the master ring having a concentric annular shoulder and,

l Lasa-:e1

a ledge eccentric to the outsidt' circumferencevof the ring, vthe eccentricity being so arranged astoproduce the greatest Vthxckness at the point farthest 4from the split ends -ol the ring, the se' ondary 'ring having an l approximately s herical surface eoperating with said annu ar shoulder com ensating as the secondaryring can expan for unequal Wear,'axial1y, in diferent portions of the ina-ster ring.

3; In a device of -the class descrlbed, the combination of a Isplit master ring and a split secondary ring-.coperatng therewith,l

ing an approximately spherical surface rising from the inner diameter ofthe said meeting surfaceof the secondary ring.

lJeAs a new article'of manufacture, a

packing constructed of two rings whose combined' oiitline in cross-section is substantially rectan lar and" whose meeting faces are dispose at right an les to the axis of the cylinder, each of sai rings having separated 'ends and said separated ends being positioned out of registration with each other, each of said rings being constructed of resilient material, the outer rin having an annular shoulder concentric wi the cylinder andren inwardly -projecting ledge eccentric .thereto for producing uniform pressure against the inside 'of the' cylindelgthe inner ring having an approximately spherical surface Vrising from the inner edge of itsmeeting face, whereby the,-

unequal wear axially of the outer ring due to the presence of more .metal at one point4 of its circumference than another isV compensated for by the spherical surface on the inner ring.

In witness whereof, I hai/'e hereuntosubscribed my name.

JAMES A. CHARTER.

Witnesses:

M. S. Rosanzwam, E'rrA L. Wm'ra. 

